Grinding wheel truing apparatus



April 7, 1942- 2 J. oLsoN 2,279,092

' GRINDING WHEEL TRUING APPARATUS Filed Feb. "7, 1941I 2 sheets-sheet 1F575 l F572 www April 7, 1942. J, OLSYQN 2,279,092

GRINDING WHEEL Taurus APPARATUS Filed Feb. 7', 1941 2 sheets-sheet 2Patented Apr. 7, 1942 GRINDING WHEEL TRUING ABPARATS Jolm Olson,Leicester, Mass., assignor to Norton Company, Worcester, Mass., acorporation of Massachusetts Application February 7, 19111, Serial No.377,883

4 Claims.

rlhe invention relates to grinding machines. and more particularly to agrinding wheel truing apparatus for producing a radius on the peripheryof a grinding wheel.

One object of the invention is to provide a simple and thoroughlypractical radial truing device for a grinding machine. Another object ofthe invention is to provide a radial truing device which ls arranged fortruing a radius on either corner of the peripheral face of a grindingwheel or a radius which extends from one side of the wheel to the other.

Another object of the invention is to provide a suitable adjustable stopmechanism whereby the movement of the diamond or truing tool may beaccurately stopped after completing its circular movement to generate aradius on the desired portion of the grinding wheel face. Other objectswill be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the fea tures of construction,combinations of elements, and arrangements of parts, as will beexemplifled in the construction to be hereinafter described, and thescope of the application of which Will be indicated in the followingclaims.

In the accompanying drawings in which is shown one of various possibleembodiments of the mechanical features of this invention,

Fig. l ,is a side elevation, partly broken away and shown in section, ofthe improved grinding wheel truing apparatus;

Fig.' 2 is a plan View of the improved truing apparatus;

Fig. 3 is a fragmentary cross sectional View, taken approximately on theline 3-3 of Fig. l, showing the rotatable stop member in its variouspositions in full and dotted lines;

Fig. 4 is a fragmentary detail view, on an enlarged scale, of therotatably adjustable stop;

Fig. 5 is a similar fragmentary view, on an enlarged scale, showing thestop lugs in the opposite position;

Fig. 6 is a similar fragmentary view, on an enlarged scale, showing thestop lugs in an intermediate position to facilitate movement of thetruing tool in a semi-circular path;

Fig. 7 is a fragmentary sectional view, on an enlarged scale, showingthe truing apparatus arranged for truing a radius on the lower corner ofthe grinding wheel;

Fig. 8 is a similar fragmentary View, on an enlarged scale, showing thetruing apparatus arranged for truing a radius on the other corner of theabrasive wheel: and

Fig. 9 is a similar view, showing the truing tool arranged for moving ina semi-circularpath to true a radius extending across the entireperipheral face of the grinding wheel.

A grinding wheel truing apparatus has been illustrated in the drawings,comprising a base l0 .which is providedwith a dovetailed surface l-lwhich in turn mates with a correspondingly shaped surface formed on theupper faceof a grinding machine table l2. The base Hl is arranged to beremovably attached to the table l l by means of a clamping block I3 anda manually operable clamping screw I4.

The base l0 serves as a support for a pivotally mounted C-shaped frameIE. The frame E5 is provided with trunnion studs E6 and Il which arejournalled in anti-friction bearings i8 and i3. The anti-frictionbearings I8 and I9 are supported in the base Ill. The pivotal axis of`the trunnion I6 is aligned with the axis of the trunnion stud Il andtheir axes are arranged in a substantially vertical position. TheC-shaped` frame l5 serves as a support for a truing tool holder 20 whichis adjustably clamped in position on the frame l5. Thetruing toolholder'Zi) adjustably supports a truing tool, such as a diamond 2l,which is arranged to engage and true the peripheral face of a grindingwheel 22. The grinding wheel 22 is supported on a rotatable spindle 23which is journalled in suitable bearings (not shown) in the grindingmachine. The truing tool holder 20 fits within a horizontally positionedcylindrical aperture formed in the C shaped frame l5 and is arranged sothat it may be adjusted in a plane normal vto the pivotal axis of theC-shaped frame l5 and held in adjusted position by means of a clampingscrew 24. By adjusting the truing tool holder 20, the diamond or truingtool 2l may be accurately positioned relative to the pivotal axis of theC-shaped frame l5 so that it will generate a curved face on theperiphery of the grinding wheel of a desired and predetermined radius.

A sleeve 26 is keyed to the upper end of the trunnion stud Il. Thesleeve 26 is provided with an integrally formed enlarged heady 21 whichserves as an end cap to enclose the aperture at the top of the frame it.A manually operable handle 28 is iiXedly mounted to `the cap 2l and`extending lugs 29 and 30 (Fig. 2) which serve as supports for adjustablestop screws 3| and 32. The stop screws 3| and 32 are arranged in thepath of the handle 28 so that as it is swung in a circular path ineither direction, either the stop screw 3| or the stop screw 32 willserve to limit the movement of the truing tool and prevent it fromcutting a groove in the side face of the grinding wheel. By adjustingthe stops 3| and 32, the swinging movement of the truing tool may belimited as desired. As shown in Fig. 2, the stops are set so that themanually operable handle 28 may be swung from a full line position in acounterclockwise direction into position 28a to swing the C-shaped frameI5 from a full line position (Fig. 7) into a broken line position |5awhich in turn transmits a corresponding movement to the truing tool 2|to swing it into position 2Ia, thus generating a curved faceor radius onthe lower peripheral corner of a grinding wheel 22 (Fig. 7). n

In'truing a radius on either corner of the grinding wheel, it isdesirable to denitely limit the arcuate swinging movement of the diamondto prevent it from undercutting the surface so that an element of theradius or curved face is tangent to an element of the peripheral surfaceof the grinding wheel. To accomplish this result, a stopmechanism isprovided comprising a rotatable member 35 which is rotatably supportedon a stud 36 which is in turn xedly mounted relative to the base I0. Themember 35 is provided with a pair of oppositely extending, staggeredstop lugs 31 and 38. The rotatable stop member 35 is arranged to belocated in one ofk three operating positions by means of a springpressedball 40 (Fig. 2) which is carried bythe member 35 and arranged to engageapertures formed in the adjacent end face 4I formed integral with theframe I0. ber 35 is positioned as shown in Figs. l, 2, 3 and 4, thetruing apparatus is set up for generating a radius on the lower cornerof the grinding wheel 22 (Fig. 7). The stop lug 38 projects upwardly andserves to limit themovement of the actuating lever 28 as it swings in a.clockwise direction. At this time the stop lug 3'| projects downwardlyand is arranged in the path of an adjustable stop screw 42 which servesdefinitely to locate the rotatable stop member 35 and thus limit thearcuate swinging movement of the diamond 2| when it reaches the fullline position as shown in Fig. 7. In this position of the rotatable stop35, the operating lever 28 together with the C-shaped frame I5 and thediamond or truing tool 2| may be swung through 90 degrees in acounterclockwise direction into the broken line positions I5a and 2Ia,respectively, as shown in Fig. 7. The stop screw 42 is screw threadedthrough a portion I0 of the base. l

If it is desired to true a radius on the other or upper corner of thewheel 22 (Fig. 8), the rotatable stop member 35 is rotated 180 degreesinto the position illustrated in Fig. 5, so that the stop lug 31 servesto limit the counterclockwise movement of the manually operable lever28, and in which position an adjustable stop screw 43 which is screwthreaded through a portion of the frame I (Fig. 3) serves definitely tolocate the rotatable member 35. In this position of the rotatable stopmember 35. it will be readily apparent that the truing tool 2| may beswung to 90 degrees from the full line position (Fig. 8) into the brokenline position 2lb, in which position the clockwise swinging movement ofthe manu- When the stop memally operable lever 28 is limited by means ofthe stop screw 3| (Fig. 2).

If it is desired to true a semi-circular radius extending from one sideof the wheel to the other on the periphery of the wheel, asv shown inFig. 9, the rotatable stop member 35 is shifted into the position shownin Fig. 6, in which position the manually operable control lever 28 isfree to swing through 180 degrees and is limited in its path of swing bythe adjustable stop screws 3| and 32, respectively (Fig. 2).

By the provision of the stop members above described, it will be readilyapparent that a radius may be generated on either corner of the wheel ora radius which extends across the entire face thereof, depending uponthe setting of the rotatable stop member 35. While the disclosure in thedrawings illustrates the apparatus as being applicable to the forming ofa convex radius on the periphery of the grinding wheel, it will bereadily apparent that the apparatus is equally applicable for generatinga concave radius at either corner of the wheel or to produce a groovedface on the periphery of the grinding wheel, it being merely necessaryadjustably to advance the truingvtool holder 20 toward the right(Fig. 1) so that the truing tool 2| projects toward the right of theaxes of the C-shaped frame I5 by a distance equal to the concave radiuswhich it is desired to produce.

The operation of the improved truing apparatus will be readily apparentfrom the foregoing disclosure. The truing apparatus base I0 is placed inposition on a grinding machine table or support I2 and is clamped inposition thereon by means of the clamping member I3 and the manuallyoperable screw I4. The diamond or truing tool 2| and its supportingholder 20 are then adjusted to the desired position relative to the axisof the C-shaped frame I5 to generate the desired convex or concaveradius on the operative face of a grinding wheel 22, after which thetruing tool is 'clamped in adjusted position. The stop screws 3| and 32together with the stop screws 43 and 42 are adjusted to limit thearcuate swinging movement of the truing tool as desired, so that it willswing through an arc of exactly degrees on either corner of the grindingwheel, as shown in Figs. 7 and 9, or through degrees as shown in Fig. 9.The stop screws 42 and 43 are then adjusted to limit the swingingmovement of the truing tool 2|. The rotatable stop member 35 is thenrotated or indexed to the desired position and the apparatus is thenready for operation. The grinding wheel 22 may then be advanced towardthe truing tool 2| by the common, well-known feeding mechanism of thegrinding machine and the truing tool 2| oscillated to true off the faceof the wheel and thus generate the desired and predetermined radius onthe periphery thereof. i

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. In a truing apparatus for grinding machines having a truing apparatusbase, means to clamp said base on a grinding machine, a pivotallymounted frame on said base which is arranged to swing in a circularpath, pivotal bearing supports for the ends of said frame to support iton a substantially vertical axis, a truing tool adjustably supported onsaid frame, a manually operable lever to oscillate said frame and truingtool, a pair of adjustable stop screws on said frame to limit thearcuate movement of said lever in either direction to determinetheextreme end positions of said truing tool, a rotatable stop member onsaid frame having a pair oi oppositely extending staggered stop lugs,said stop lugs being arranged in an intermediate position to facilitatean arcuate movement of the truing tool through 180 degrees, and in itsend positions to limit the arcuate movement of the truing tool toward aposition with the truing tool axis normal to the axis of the grindingwheel to facilitate truing a quarter-circular face on either corner ofthe grinding wheel.

2. In a truing apparatus for grinding machines having a truing apparatusbase, means to clamp said base on a grinding machine, a pivotallymounted frame on said base which is arranged to swing in a circularpath, pivotal bearing supports for the ends of said frame to support iton a substantially vertical axis, a truing tool adjustably supported onsaid frame, a manually operable lever to oscillate said frame and truingtool, a pair of adjustable stop screws on said frame to limit thearcuate movement of said lever in yeither direction to determine theextreme end positions of said truing tool, a rotatable stop member onsaid frame having a pair of oppositely extending staggered stop lugs, apair of opposed staggered stop screws each arranged in the path of oneof said stop lugs to determine the extent of rotation of said stopmember, said stop lugs being arranged in an intermediate position tofacilitate an arcuate movement of the truing tool through 180 degrees,and in its end positions to limit the arcuate movement of the truingtool toward a position with the truing tool axis normal to the axis ofthe grinding wheel to facilitate truing a quarter-circular face oneither corner of the grinding wheel.

3. In a truing apparatus for grinding machines having a truing apparatusbase, means to clamp said base on a grinding machine, a pivotallymounted frame thereon which is arranged to swing in a circular path,pivotal bearing supports for the opposite ends of said frame, a truingtool adjustably supported on said frame, a manually operable lever tooscillate said frame and tool to true a curved face on the periphery ofa grinding wheel, a pair of spaced adjustable stop screws on said frameto limit the arcuate movement of said lever in either direction wherebysaid truing tool may swing in a semi-circular path. a rotatable stopmember on said frame having a pair of oppositely extending staggeredstop lugs, a pair of adjustably staggered stop screws each arranged inthe path of one of said v stop lugs accurately to position saidrotatable stop member so that the oppositely extending stop lug lies inthe path of the manually operable lever to limit the arcuate swingingmovement of the truing tool in one direction so that its axis lies in apath substantially normal to the axis of the grinding wheel.

4. In a truing apparatus for grinding machines having a truing apparatusbase, means to clamp said base on a grinding machine, a

pivotally mounted frame thereon which is arranged to swing in a circularpath, pivotal bearing supports for the opposite ends of said frame, atruing tool adjustably supported on said frame, a manually operablelever to oscillate said frame and tool to true a curved face on theperiphery of a grinding wheel, a pair of spaced adjustable stop screwson said frame to limit the arcuate movement of said lever in eitherdirection whereby said truing tool may swing in a semi-circular path, arotatable stop member on the frame having a pair of oppositely extendingstaggered stop lugs, a pair of adjustable staggered stop screws eacharranged in the path of one of said stop lugs accurately to positionsaid rotatable stop member in its extreme position so that either one orthe other of said oppositely extending stop lugs will limit the arcuateswinging movement of the tool in a quarter-circular path at eithercorner of the grinding wheel.

JOHN OLSON.

